Researchers say that an experimental drug can not only reduce damage to muscles during a heart attack, but also lower bleeding.

Scientists at the Washington University School of Medicine in St. Louis conducted several tests on animals and have found that the investigational drug APT102 can help treat heart attack patients.

"This medication, known as APT102, has the potential to change the paradigm for how heart attack patients initially are treated," said senior author Dana Abendschein, PhD, associate professor of medicine and of cell biology and physiology at the Washington University. "This also may be a better way to treat strokes caused by or associated with a blood clot."

Heart attacks are usually caused by atherosclerosis, which occurs when there is too much of cholesterol in the body. Fat and calcium accumulate in the artery and form plaques. These plaque often restrict blood flow in the arteries. A heart attack occurs when the heart doesn't get enough oxygen. The condition is the leading cause of death in men as well as women in the U.S.

The researchers said that currently drugs that are used to treat heart attack often lead to tissue damage. The treatment removes blood clot from the artery, but leaves behind molecules from the dead cells. The molecule - adenosine triphosphate (ATP) - is inflammatory; adenosine diphosphate (ADP) then rushes through the artery and cause more clotting.

The study is published in the journal Science Translational Medicine and is funded by the National Institutes of Health (NIH) Small Business Innovation Research Grant and by APT Therapeutics Inc., the developer of APT102.

APT102 mimics human protein apyrase, which changes ATP and ADP into a harmless molecule called adenosine monophosphate. Another enzyme changes this molecule into adenosine, which is good for the heart.

"Adenosine opens the blood vessels, increases blood flow and also has a protective effect on the lining of the vessels," said Abendschein in a news release. "It takes the bad products away and produces a good byproduct that's protective."

The study was conducted on 21 dogs. Standard drugs were used to dissolve blood clots in the arteries. Eight of the dogs received heart-attack drug clopidogrel, which is a blood thinner; seven were given low doses of APT102; and six were given high doses of the test drug.

The researchers found that the experimental drug reduced risk of heart muscle damage in the dogs.